We present results of measurements of cosmogenic 10Be, 26Al and 36Cl, and the indigenous
(intrinsic) concentrations of the stable elements Be, Al and Cl in 120–200 kyr old corals from Barbados and
Puerto Rico. The concentration levels of these radionuclides in the corals lie in the range 104 to 108 atoms/g.
A comparison of the measured nuclide concentrations with those expected to be produced in the corals by
nuclear interactions of energetic cosmic radiation shows that (i) the radionuclides 26Al and 36Cl are derived
from in situ cosmic ray interactions in the corals after their formation, but that (ii) the radionuclide 10Be owes
its provenance in the coralline lattice primarily due to incorporation of dissolved beryllium in seawater in the
lattice structure of the corals.